Compared with other mental health conditions or psychiatric presentations, such as self-harm, which may be seen in emergency departments, eating disorders can seem relatively rare. However, they have the highest mortality across the spectrum of mental health, with high rates of medical complications and risk, ranging from hypoglycaemia and electrolyte disturbances to cardiac abnormalities. People with eating disorders may not disclose their diagnosis when they see healthcare professionals. This can be due to denial of the condition itself, a wish to avoid treatment for a condition which may be valued, or because of the stigma attached to mental health. As a result their diagnosis can be easily missed by healthcare professionals and thus the prevalence is underappreciated. This article presents eating disorders to emergency and acute medicine practitioners from a new perspective using the combined emergency, psychiatric, nutrition and psychology lens. It focuses on the most serious acute pathology which can develop from the more common presentations; highlights indicators of hidden disease; discusses screening; suggests key acute management considerations and explores the challenge of mental capacity in a group of high-risk patients who, with the right treatment, can make a good recovery.